1. Chapter 6 Ionic and Molecular Compounds
Lecture Presentation
Chapter 6 Ionic and Molecular Compounds
Karen C. Timberlake

2. Chapter 6 Ionic and Molecular Compounds
Pharmacy technicians work under the supervision of a pharmacist, and their main responsibility is to fill prescriptions by preparing pharmaceutical medications. They obtain the proper medication, calculate, measure, and label the patient’s medication.

3. Chapter 6 Readiness
Key Math Skills
Using Positive and Negative Numbers in Calculations (1.4B)
Solving Equations (1.4D)
Core Chemistry Skills
Writing Electron Configurations (4.7)
Drawing Lewis Symbols (4.8)

4. 6.1 Ions: Transfer of Electrons
Atoms form positively charged ions when they lose electrons and negatively charged ions when they gain electrons.
Ionic bonds are formed by the strong attractive forces between positive and negative ions.
Learning Goal Write the symbols for the simple ions of the representative elements.

5. Ionic and Covalent Bonds
Chemical bonds are formed when atoms lose, gain, or share valence electrons to acquire an octet of eight valence electrons (octet rule).
Ionic bonds occur when valence electrons of a metal atom are transferred to the atom of a nonmetal.
Covalent bonds occur when nonmetal atoms share electrons to attain a noble gas arrangement.

6. Ionic and Covalent Bonds

7. Positive Ions: Metals Lose Electrons
In ionic bonding, ions form when atoms gain or lose their valence electrons to form a stable electron configuration. Metals, Group 1A (1), Group 2A (2), and Group 3A (13)
have low ionization energies.
readily lose one or more of their valence electrons to form ions with a positive charge.
lose electrons until they have the same number of valence electrons as the nearest noble gas, usually eight valence electrons.

8. Positive Ions: Loss of Electrons
Sodium atoms in Group 1A (1) are neutral, with 11 electrons and 11 protons, they
lose one electron to have the same number of valence electrons as neon and a filled energy level.
will form an ion with 10 electrons, 11 protons, and an ionic charge of 1+: Na+.

9. Positive Ions: Loss of Electrons
Magnesium atoms in Group 2A (2) are neutral, and they have 12 electrons and 12 protons. They
will lose 2 electrons to have the same number of valence electrons as neon and a filled energy level.
form an ion with 10 electrons, 12 protons, and an ionic charge of 2+: Mg2+.

10. Negative Ions: Nonmetals Gain Electrons
Nonmetals, Group 5A (15), Group 6A (16), and Group 7A (17)
have high ionization energies.
readily gain one or more valence electrons to form ions with a negative charge.
gain electrons until they have the same number of valence electrons as the nearest noble gas, usually eight valence electrons.
Core Chemistry Skill Writing Positive and Negative Ions

11. Negative Ions: Gain of Electrons
Chlorine atoms in Group 7A (17) are neutral, and they have 17 electrons and 17 protons. They
will gain one electron to have the same number of valence electrons as argon.
form an ion with 18 electrons, 17 protons, and a charge of 1−: Cl−.

12. Formulas, Names of Common Ions

13. Ionic Charges, Group Numbers
We can use the group numbers in the periodic table to determine the charges for the ions of the representative elements.

14. Chemistry Link to Health: Important Ions in the Body
Ions are important in regulating body functions.
Ion
Occurrence
Function
Source
Na+
Principal cation outside the cell
Regulation and control of body fluids
Salt, cheese, pickles K+
Regulation of body fluids and cellular functions
Bananas, potatoes, orange juice, milk
Ca2+
Cation outside the cell; found in bones
Major cation in bones, needed for muscle contractions
Milk, yogurt, cheese, greens, spinach
Mg2+
Essential for certain enzymes, muscles, and nerve control
Chlorophyll, nuts, grains

15. Study Check
Write the formula and symbol of an ion with 16 protons and 18 electrons.

16. Solution
Write the formula and symbol of an ion with 16 protons and 18 electrons.
The element with 16 protons is sulfur, with the symbol S.
An ion of sulfur with 18 electrons gives sulfur a charge of 2−.
The sulfide ion is S2−.

17. Study Check
Consider the elements calcium and chlorine.
Identify each as a metal or a nonmetal.
State the number of valence electrons for each.
State the number of electrons that must be lost or gained for each to acquire an octet.
Write the symbol, including its ionic charge, and name of each resulting ion.

18. Solution
Consider the elements calcium and chlorine.
Identify each as a metal or a nonmetal. metal = calcium nonmetal = chlorine
State the number of valence electrons for each. Calcium has two valence electrons. Chlorine has seven valence electrons.

19. Solution Consider the elements calcium and chlorine.
State the number of electrons that must be lost or gained for each to acquire an octet. Calcium will lose two electrons to acquire an octet. Chlorine will gain one electron to acquire an octet.
Write the symbol, including its ionic charge, and name of each resulting ion. Ca2+ calcium Cl− chloride